The present disclosure relates to subterranean operations and, more particularly, to systems and methods for monitoring and characterizing well bores, subterranean formations, and/or fluids in a subterranean formation.
Performance of subterranean operations entails various steps, each using a number of devices. Many subterranean operations entail introducing one or more well servicing fluids into the subterranean formation. For instance, drilling operations play an important role when developing oil, gas or water wells or when mining for minerals and the like. During the drilling operations, a drill bit passes through various layers of earth strata as it descends to a desired depth. Drilling fluids are commonly employed during the drilling operations and perform several important functions including, but not limited to, removing the cuttings from the well to the surface, controlling formation pressures, sealing permeable formations, minimizing formation damage, and cooling and lubricating the drill bit.
Properties of the drilling fluid are typically monitored during drilling operations. For instance, it is often desirable to accurately measure hydrocarbon gas concentrations of the drilling fluid as it leaves the well bore. The level of the hydrocarbon gas in the drilling fluid may affect how the well is to be drilled as well as the safety of the drilling rig and personnel involved. Moreover, the concentration of hydrocarbon gases and other components present in the drilling fluid may be indicative of the characteristics of the formation being drilled and the drilling environment. Accordingly, the analysis of drilling fluids and the changes they undergo during drilling operations may be important to the methods of drilling as well as the efficiency of the drilling operations. Consequently, during drilling, completion and testing of a well bore, it is desirable to obtain analytical measurements of the fluids that are returned to the surface from the well bore.
One method for collecting and analyzing the drilling fluid involves submerging a rotor within a vessel into the drilling fluid as the drilling fluid exits the well bore. Typically, the placement of this “gas trap” is in an open pit or header box which is exposed to atmospheric conditions. The drilling fluid is agitated as it enters into and exits out of the vessel and some of the gasses dissolved therein evaporate and escape the confines of the fluid. These vaporized gases are then collected and processed by analytical methods to determine the presence and levels of hydrocarbons and other components in the drilling fluid.
However, the usefulness and reliability of information obtained from monitoring of drilling fluids may be limited in several respects. First, many components present in the formation may not be detected in the drilling fluid if the type of drilling fluid used is not capable of absorbing or dissolving those components. The dissolution or absorption of certain components into the drilling fluid in larger quantities also may mask other components that are present in the formation in smaller quantities. Moreover, because the drilling fluid is typically circulated throughout the entire well bore, it is generally not possible to determine if a particular species is present at an interval above the bottom of the well bore.
While the present disclosure is susceptible to various modifications and alternative forms, specific example embodiments have been shown in the figures and are herein described in more detail. It should be understood, however, that the description of specific example embodiments is not intended to limit the invention to the particular forms disclosed. On the contrary, this disclosure is to cover all modifications and equivalents as illustrated, in part, by the appended claims.